documentation.txt

File Breakdown

    constants.py
        This file holds constant values such as:
            ACCELERATION_ID, SPEED_ID, POSITION_ID: Index values for accessing acceleration, speed, and position in arrays.
            EPSILON: A small value used for comparisons to avoid floating-point precision issues.

    planningerror.py
        Contains a custom PlanningError class which extends Python's Exception class. This is raised when a trajectory cannot be planned due to physical constraints or numerical problems.

    trajectory.py
        Defines the Trajectory class.
            Stores and computes trajectory profiles.
            Uses properties like dof (Degrees of Freedom), time, and trajectory for tracking the planned motion.
            The __call__ method enables the Trajectory instance to return the acceleration, speed, and position for a specific time instance.

    trajectory_planner.py
        Defines the abstract base class TrajectoryPlanner with an abstract method plan_trajectory().
        Contains utility functions like _check_shape to ensure that input parameters (positions, velocities, etc.) are consistent.

    scurve_planner.py
        Implements the main logic of the S-curve planner through the ScurvePlanner class, which inherits from TrajectoryPlanner.
        Key functionalities include:
            S-Curve Feasibility Checks (__scurve_check_possibility): Ensures that given initial/final conditions (position, velocity, etc.) can be achieved within physical limits.
            Speed Calculation (__compute_maximum_speed_reached and __compute_maximum_speed_not_reached): Computes the time intervals and constraints to achieve the motion.
            Trajectory Planning (__plan_trajectory_1D and __scurve_profile_no_opt): Generates the time intervals for acceleration/deceleration and cruising to move from the initial to the final position under the S-curve profile.
            Trajectory Generation (__get_trajectory_func and __get_trajectory_function): Provides a callable function to compute the position, speed, and acceleration at any time.

    plotting.py
        Provides a plot_trajectory() function that uses matplotlib to visualize the planned trajectory.
            It creates three subplots per degree of freedom to show acceleration, speed, and position profiles over time.

    extract_trajectory_profiles.py
        Implements a utility function extract_trajectory_profiles() which samples the planned trajectory at discrete time intervals and extracts the acceleration, speed, and position values.
        This function can be used for further analysis or plotting.

    main.py
        This file likely acts as the main entry point, integrating all the different classes and functions to execute the motion planning process and visualization.

Description of Main Components

    Trajectory Class:
        Stores the S-curve motion trajectory.
        Allows retrieving position, speed, and acceleration at any given time.

    ScurvePlanner Class:
        Implements the core logic of planning a trajectory using the S-curve motion profile.
        Ensures the planned motion adheres to physical constraints such as maximum velocity, acceleration, and jerk (rate of change of acceleration).
        Returns a Trajectory object that can be used to sample the motion over time.

    Error Handling:
        The PlanningError class raises custom exceptions when trajectory planning fails due to infeasibility.

    Plotting and Profiling:
        plot_trajectory(): Plots acceleration, speed, and position profiles.
        extract_trajectory_profiles(): Extracts motion data for further analysis.